My last of 4 is off to high school

. I am nervous, happy, and a little sad too. How could my baby be in high school??? I drove him to the bus stop this morning because it was raining. After he got on the bus I just sat there for a little....I remember sending him in the door of pre school, sitting in the parking lot crying and calling my dad to tell him I was sad. My dad passed away 5 years ago and now I have no one to call. I really needed to hear his voice today to tell me its ok and my little guy is growing up.
Also today is my oldest birthday today. He is 23

this is also hard to believe!!!
What is happening?????